Automatic cut-off device for gas burners



May 29, 1934. yv KNlGHT 1,960,973

AUTOMATIC CUT-OFF DEVICE FOR GAS BURNERS Filed Sept. 16; 1929 I N V EN TOR.

Zd do; By 7 K44 WWW aim A TTORNEYS Patented May 29, 1934 UNITED STATES I 1.960.913 AUTOMATIC eo-r-orr nn'vrca ron GAS BURNERS George W. Knight, Milwaukee, Wis., assignor oi one-third to Herbert W. White and one-third to Nick Brazy, both of Milwaukee, Wis.

Application September 16, 1929, Serial No. 393,099

'1 Claims. (01. 158-1172) This invention relates to improvements in automatic cut-off devices for gas burners.

It is the primary object of the invention to provide a novel, simplified and compact arrangement of gas cock and control mechanism in such form as to facilitate installation on gas stoves and the like for providing effective means for closing the gas cock in the event that the flame controlled thereby is extinguished accidentally.

It is a further object of the invention to provide a novel and improved cut-off device in which any accident disconnecting a control member from the actuating thermostat therefor, will also result in shutting off fuel leading to the burner.

While I have referred and shall refer throughout the appended specification and claims to the control of gas, it will be understood by those skilled in the art that the device herein disclosed is adapted also for use in controlling any supply of fuel, whether gaseous or liquid, in its passage to a burner. It may also be'used to control an electrical switch where desired.

In the drawing:

Figure 1 is a side elevation of a burner and a gas cook control device applied thereto in accordance with this invention, parts being broken away.

Figure 2 is an enlarged detail view in section through the gas cock and control mechanism.

Figure 3 is a section taken on line 33 of Fig. 2.

Figure 4 is a section similar to Fig. 3 showing the parts in the position which they occupy when the burner is in use.

Like parts are identified by the same reference characters throughout the several views.

The burner 5 is supplied with fuel from the header 6 subject to the control of a valve plug '7 provided with a seat at 8 in the fitting 9 interposed between the header 6 and the burner passage 10. The fitting 9 has an exteriorly threaded sleeve extension at 11 receivable in a tapped opening in the header 6 as shown in Fig. l, and an oppositely disposed sleeve 12 leading to the usual air control portion of the burner passage 10. The valve plug 7 is transversely ported at 13 and is held to its seat by a compression spring 14 in the usual way.

The valve plug 7 is provided at 15 with a shoulder beyond which extends its stem 16 to which the control handle 1'7 is attached. Mounted for rotation on the shoulder and surrounding the stem for rotation within the cavity 18 of fitting 9, is a rotative member 19 subject to the action of a torsion spring 20 seated at one end in the fitting and at its other end connected with the rotative member 19. Spring 20 tends constantly to rotate rotative member 19 counterclockwise as viewed in Figs. 3 and 4.

Means is provided for causing the rotative member 19 to be turned against the pressure of spring 20 by the handle 17, and, as an emergency measure, to enable the spring 20 to act through the rotative member 19 to rotate the 5 valve stem 16 and handle 1'7 in a direction to close the valve. This means may consist of a vertically projecting pin 21 carried by the torsion member and a laterally projecting pin 22 carried by the valve stem 16 and serving also to fasten thereon a collar 23 which holds the torsion member against shoulder 15. It will be obvious that when the stem is rotated in a clockwise direction the pin 22 engaging with pin 21 in position of the parts shown in Fig. 3 will cause rotation of the parts through the dotted line positions to the full line position shown in Fig. 4. From this full line position the spring 20 will tend to restore the parts toward the Fig. 3 position in which the valve is closed. In the Fig. 4 position of the parts the valve is wide open.

Mechanism is provided which is effective during the proper functioning of burner 5 to relieve the gas cock of the torsion of spring 20, thereby permitting it to remain in its wide open or in any intermediate position. Such mechanism includes a thermostatic rod 25 which extends directly above the burner and is anchored at its remote end 26 to a fitting 27 secured against movement in any suitable manner not shown and with respect to which it is adjustable for the initial setting of the parts. The free end of the ther mostatic rod 25 is connected to a plunger 28 movable within a cylinder 29 threaded into a tapped opening 30 in the side of fitting 9. A compression spring 31 tends at all times to distend the thermostatic rod 25 and to force plunger 28 into the cavity 18 within fitting 9.

Co-acting with the thermostatically controlled plunger 28 is an arm 35 formed integrally with the rotative member 19. This arm is alrcuately disposed in concentric proximity to the wall of cavity 18 and is spaced both laterally and vertically from adjacent portions of rotative member 5 19, being connected thereto solely at its end.

When the thermostatic rod 25 is cold the adjustment thereof will be such that the end of plunger 28 will be substantially tangential to the arm 35 carried by the rotative member 19. In

this position of the parts the plunger will not interfere with the free oscillation of the torsion member throughout its indicated range of movement, and the spring 20 will invariably act to return the valve plug to its closed position upon release of handle 17 by the operator.

If, however, the gas cock be manipulated to permit a flow of gas to the burner, and if the gas at the burner is ignited while the handle 17 is held in its open position, the heat of the burning gas will immediately cause sufficient expansion of the thermostatic rod 25 to thrust plunger 28 inwardly in the path of movement of the end of arm 35 as shown in Fig. 4. The plunger 28 will now take the torsional thrust of spring 20, thereby holding pin 21 stationary in its Fig. 4 position. The gas cock can now be manipulated as desired, the valve stem 16 being freely rotatable toward its closed position and wholly relieved of the torsion of spring 20, so that it will remain in any of an infinite number of intermediate positions such as those shown for pin 22 in dotted lines in Fig. 4.

If the flame at burner 5 is extinguished either accidentally or intentionally through manipulation of the handle 17, rod 25 will cool and in cooling will contract sufiieiently to withdraw plunger 28 from the path of arm 25, thereby releasing rotative member 19 and causing pin 21 to move under the torsion of spring 20 to its Fig. 3 position. If the flame has been extinguished intentionally by manipulation of the valve, pin 22 will already be in the position indicated in Fig. 3. If, however, the extinguishing of the flame has been unintentional, as by the boiling over of water from a kettle heated by the flame, the pin 21 will, in the course of its movement, pick up pin 22 in any position thereof and restore it to the closed position of the valve.

My purpose in spacing arm 35 from the remaining parts of rotative member 19 is to permit the use of a safety feature efiective in the event that the rod 25 becomes broken or disconnected. I have provided at 37 an aperture in plunger 28 suificiently large.,to receive arm 35 if the plunger is ever forced by spring 31 to a position where its end abuts the surface 38 of rotative member 19.

It will be obvious that in this position of the parts, the valve cannot remain open until the thermostatic control rod 25 has been repaired so that the end of plunger 28 will again be movable into the path of arm 35. If breakage of the thermostatic rod occurs with the parts in the Fig. 4 position, plunger 28 will be thrust by spring 81 past the end or shoulder of arm 35, and as soon as the arm registers with opening 37 it will pass therethrough under torsion of spring 20 in a valve closing direction. If breakage occurs at a time when the valve is already closed as shown in Fig. 3, the initial manual opening of the valve will allow plunger 28 to pass arm 35 as above described, and the valve will immediately close when released by the operator.

The foregoing description and the drawing disclose a gas control device which provides trip mechanism for automatically shutting oil a gas cont ol valve when gas ceases to flow and which at the same time leaves the valve free to be manually shut off. It is obvious that when the valve is manually closed, the thermostatic rod will contract and permit the trip mechanism to engage the valve and hold it in its closed position.

I claim:

1. A device of the character described comprising the combination with a control member, of an oscillatable actuating part operatively associated with said member provided with an arm, a transversely reciprocable detent having a limited range of movement and provided with means operative at each end of said range to clear said arm and at an intermediate position to abut said arm, a torsion spring acting on said part for the actuation of said member thereby, said detent being operative to relieve said member of the thrust of said spring pressed part when abutting said arm, and means normally limiting the movement of said detent beyond said intermediate position and means operative to automatically move said detent to a position for clearing said arm upon failure of said last mentioned means.

2. In a device of the character described, the combination with a spring braced part mounted for oscillation and provided with a radially spaced arcuately movable arm, of a detent mounted for reciprocation across the path of said arm and provided with a portion operatively engageable with said arm in an intermediate detent position and an opening through which said arm is receivable in another position, and means for manipulating said detent to and from the path of said arm while normally restricting it from movement to said last mentioned position, and means operatively urging said detent toward said last mentioned position.

3. In a device of the character described, the combination with a control member provided with a handle, of an actuating part operatively associated with said member and spring pressed for movement in a given direction for the operation of said member, said part and member being provided with interacting portions whereby said part is normally operative to move said member in a given direction, a detent engageable with said part and movable in either of two directions from its point of engagement from said part, said detent being operable when engaged with said part to relieve said member of the thrust of said spring pressed parts, and said handle being operative through said member for the manipulation of said part to a position where it may be engaged by said detent, a spring acting on said detent and tending to thrust it in one of said directions away from the point of engagement with said part, and motion transmitting means operatively associated with said detent opposing said spring and including means operable for the adjustment of said detent through a range including only the other of said directions of movement from the point of engagement with said part.

4. In a device of the character described, the combination with a control member and a spring pressed part having means operatively interacting for transmitting motion in a predetermined relative direction of movement, said member being operable to actuate said part in a direction to increase the pressure of its spring, a movable detent for said part operatively efi'ective in one position of said part to restrain its spring pressed movement, whereby to relieve said member of the pressure of said part, said detent and the portion of said part engaged thereby having a limited relative extent in the direction of detent movement whereby said detent is disengageable from said part in either of two directions of movement, a thermostat provided with motion transmitting means operatively associated with said detent and operable through a range including only one of said directions of movement from its point of engagement with said part, and a spring operatively pressing said detent toward its other direction of movement from said point of engagement with said part, whereby to effect the release of said part from said detent in the event of breakage of the motion transmitting means from said thermostat.

5. In a device of the character described, the combination with a rotatable control member, of a rotatable part operatively provided with means subjecting it to torsion, said member and part being operatively formed for interaction in a di reciion to deliver rotative movement from said part to said member, and an arm carried by said part and having a terminal portion spaced therefrom, a detent cngageablc with said portion and having a limited extent transversely of said portion whereby to be discngageable from said portion in either of two directions from its point of engagement therewith. actuating means operaiively associated with said detent, and means normally operating said actuating means through a range including only one of said directions of movement from said point, said detent being biased for movement in the other of said direc tions from said point upon the breakage of said actuating means.

6. In a device of the character described, the combination with a rotatable control member, of a part provided with means interacting with said control member for the transmission of rotative movement between said part and member, a spring subjecting said part to torsion in a direction to rotate said member, an arm carried by said part and having a portion spaced there-' from, a detent engageable with said arm in a position to which said part is adjustable against the torsion of said spring by means of said memher, said detent being operative to relieve said member of the thrust of said spring pressed part when the detent is engaged with said arm, said detent comprising a plunger provided with an opening adjacent its end and normally engaging with its end a portion of said arm, receivable into said opening, said detent being so disposed with relation to said portion that movement of said detent in either direction from the point of engagement aforesaid will free said part for the operative rotative actuation of said member.

7. In a device of the character described, the combination with a chambered casing, of a control member rotatably mounted therein, a motion transmitting part co-axially mounted for rotative movement in said chamber, a spring housed beneath said part within said chamber and operatively connected to act upon said part, means carried respectively by said part and by sa'd member and operative to interact for the transmission of spring pressed movement from said part to said member, an arm carried by said part within said chamber, and a detent guided for movement to and from said casing in said chamber and operative to interact with said arm in a position to which said part is adjustable against the pressure of said spring through the manipulation of said member, whereby in such position to relieve said member of the thrust of said part, said detent being apertured to receive said arm when the detent is thrust beyond the point of normal engagement, a spring acting on said detent in a direction to register the detent aperture with said arm, a thermostat for the manipulation of said detent, and control means connecting said thermostat with said detent, said thermostat and control means normally restraining said detent to a position in which said aperture is out of registry with said arm.

GEORGE W. KNIGHT. 

